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71.
Kasarapu Venkataramana Chittimadula Madhuri Ch Madhusudan Y.Suresh Reddy G. Bhikshamaiah C.Vishnuvardhan Reddy 《Ceramics International》2018,44(6):6300-6310
In the present study, we investigate the fundamental properties of CeO2 by selecting La3+ (57), and Dy3+ (66) as dopants with optimized average atomic number of 61.5, which lies in between Pm3+ (62) and Sm3+ (62) in accordance with the criteria for optimum doping. A system of co-doped ceria ceramics Ce1–x–yLaxDyyO2-δ ((x, y) = (0.00, 0.00), (0.025, 0.025), (0.05, 0.05), (0.075, 0.075), (0.10, 0.10), (0.00, 0.20) and (0.20, 0.00)) as electrolytes for intermediate temperature solid oxide fuel cells were successfully prepared by a well-known sol-gel auto-combustion route. In order to obtain dense samples, the prepared pellets were sintered in air at 1300 °C for 4 h using conventional furnace and relative densities of all the samples were found to be higher than 95%. Single phase cubic structure, microstructural density and elemental composition analysis of all the samples were studied by powder X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy techniques, respectively. Raman spectroscopy analysis confirmed the formation of concentrated O2-–vacancies in the co-doped ceria system. Impedance spectroscopy measurements revealed the high value of total ionic conductivity and low activation energy for the composition Ce0.85La0.075Dy0.075O2?δ i.e., 2.08 × 10–2 S cm–1 and 0.58 eV, respectively. Linear thermal expansion analyses of all the samples revealed the matched thermal expansion coefficients. Finally, these results recommend that the Ce0.85La0.075Dy0.075O2?δ sample can be useful as a solid electrolyte in IT-SOFC applications. 相似文献
72.
《Calphad》2020
In this study, the Ga–Te binary system was reassessed by means of the CALPHAD method using a modified lattice stability parameter for Te as well as experimental data for this binary system. The two-sublattice ionic solution model was applied for the liquid phase, and the intermediate phases were described by the sublattice model. A set of self-consistent thermodynamic parameters was optimized for all the phases in the Ga–Te binary system, which reproduced the phase diagram and the thermodynamic properties well. Using the reevaluated Ga–Te system, previously assessed Ga–Se system, and modified Se–Te system, a critical evaluation of the Ga–Se–Te ternary system was performed. The calculated vertical sections, isothermal sections, and liquidus projection agreed reasonably well with the experimental data. Immiscibility in the liquid phase was observed, and the origin of this behavior is discussed from a thermodynamic perspective. 相似文献
73.
74.
以无水氯化镁和氧化镁作为中间产物,电解和热还原为两个关键方法,集成各种相关过程,构建了从水氯镁石到金属镁的综合过程网络,其中涉及24个物种、20个化学过程和25个工艺路线;建立了最低能耗分析模型用于简单和复合过程的能量分析;利用物质的标准生成焓和多温等压摩尔热容,计算得出全部反应过程及工艺过程的能量消耗和热量移除。结果表明基于还原法的最优路径是水氯镁石用石灰法转为氢氧化镁,进而煅烧成氧化镁,再铝热还原成金属镁,该过程能耗360.15 kJ/mol,放出热量–315.46 kJ/mol;基于电解法的最优路径是石灰乳法生成氢氧化镁,再煅烧成氧化镁,通过在熔融电解质中电解生成金属镁,该过程能耗738.54 kJ/mol,放出热量–135.42 kJ/mol。无水氯化镁制备耗能高,不在最优路径中。 相似文献
75.
76.
以井下作业面巷道切顶卸压施工设计为对象开展探究,结合具体工程实际,从切顶卸压爆破施工设计和爆破施工分析两个角度,对切顶卸压技术的全面应用进行总结分析,希望能够为其他矿井相似工程的开展提供借鉴与参考。 相似文献
77.
以井下供电监控及防越级跳闸运用为对象开展探究。在分析矿井供电系统运行中现存主要问题的基础上,对供电监控与防越级跳闸系统整体应用的积极意义进行了分析和总结,希望能够让更多矿井技术人员了解供电监控及防越级跳闸系统的优越性,为其在矿井中的广泛推广普及提供便利,为煤矿行业更加高效地发展提供帮助。 相似文献
78.
Manoj Kumar Nayak Vinay Shankar Pandey Dharmendra Tripathi Noreen Sher Akbar Oluwole D Makinde 《亚洲传热研究》2020,49(3):1256-1280
The present study aims to investigate the effects of thermal‐diffusion and diffusion‐thermo onan magnetohydrodynamic convective flow of viscous fluids over an exponentially stretching sheet. Thermal radiation effects are also considered in the study. This analysis is carried out in three dimensions and a similarity transformation is adopted to get a set of ordinary differential equations from a set of partial differential equations. And the Fourth‐order Runge‐Kutta method and shooting technique along with the secant method are employed to find out an iterative solution. We also analyze here the influence of the variable magnetic field, nonuniform permeability and variable chemical reaction on the fluid flow. The impact of various pertinent parameters of interest has extensively been explored through graphs and tables. The major findings of the present study are that resistive Lorentz force diminishes the fluid velocity and uplifts the thermal as well as concentration fields. Inclusion of porous matrix improves the viscous drag force which in turn augments wall shear stresses and peters out the heat and mass transfer rates from the sheet. In addition, the thermal expansion coefficient has an inverse relation with temperature. 相似文献
79.
80.